I don’t want to get too far into this but there has been a lot of chatter about the link between melting ice caps and increase/decrease/neither of volcanism. The two main articles we’re talking about are:

The long and short of the Scientific American study is that you reduce the pressure of rocks in the crust/mantle below Iceland, you generate more melting – depressurization melting of rock. If you melt the ice cap, you release a decent amount of pressure – ice is heavy and adds weight to the crust, so melting ice cap = more melting = more volcanism.

Now, my take on this is that Scientific American – and the geologists quoted – are not saying that the loss of the ice cap will increase volcanism in Iceland. They suggest that there could be a connection between the loss of ice and volcanism. This has been suggested before for the Cascades after the end of the last ice age from 12-7 k.y. ago. This could be the same for Iceland, where the loss of ice (for whatever reason) might increase overall volcanism … but is it?

WUWT take on the problem is interesting, saying that the lower pressure will cause the melting point of the rocks to change only a little bit, so you shouldn’t expect more volcanism. However, the key to this problem (in my mind) isn’t melting point but rather the volatiles dissolved in the magma. Most magmas can dissolve more volatiles (from the source of the magma, not a surface source of water) under high pressure than low pressure. If you release that pressure, then the volatiles escape in the form of bubbles and you can get an explosive eruption (like popping the top of shaken soda can). If you happen to have shallow magma chambers with volatiles near the surface and deglaciate (remove the ice), you might be prompt a reaction of the volatiles (gases) coming out of solution with the magma. Now, if you combine that with even a small amount of additional melting from lower pressures brought by deglaciation, then, maybe you could produce a temporary, larger supply of eruptible magma. Magma does not need external water to produce explosive eruptions (such as an ice cap/glacier) – and it seems that the current eruption is silicic enough to produce its own explosivity due to its viscosity and water content – so the lack of an ice cap should not preclude more explosive eruptions in Iceland.

Now, this is all just speculation on my part and I’m not trying to connect it to global warming, global cooling or the Red Sox subpar start to the season. However, what I can say is that we need to stop trying to look at every study with the lens of climate change – and especially stop treating each side of the issue as adversaries if you don’t agree with them. Science is about discussion not confrontation, but a lot of this debate becomes “Jeez, the other guys are idiots because they don’t agree with me!” A little civility and open-mindedness goes a long way.

That being said, this idea of deglaciation leading to more volcanism is fascinating and has some evidence that seems to indicate that after a major glaciation, it might happen.

Comments

Erik, I can see where deglaciation could enhance an eruption already underway, or close to eruption. I am not an expert in any of this, but I just have an idea about it. Someone once described the aftershocks of large quakes this way: you take a plastic bag, crunch it up and then release it. You get a large outburst of the bag opening up and then the small crackles as it opens further. I thought it was a pretty good illustration. I could be simular with a volcano covered with ice. Like the soda pop bottle, you shake it up and open it and boom. It fizzes all over. The more gas in the magma and the less pressure on it as it gets toward the surface, the more it is likely to blow. Just seems to make sense to me. I have a piece of obsidian that also has pumice on it. One part of that rock had a lot of gas and the other part did not and thus hardened solid. It is a unique piece that shows two things in the same rock.

I would think if you released some of the pressure by glacial melt, it would allow the volcano to release more ash, gases, and lava. You can use the analogy of a pressure cooker, too. My mother made the mistake of opening hers once before letting the steam out of it slowly and she got a second degree burn on her hand. That was not a fun experience!! I can remember her taking the pressure regulater off the top of the cooker and the steam going clear to the ceiling. I think this volcano is having a simular behavior and as the ice melts, more will be released as the magma pushes up to the point where the gases are released and it calms down a bit.

I could be wrong here, as I know it is much more complicated than a simple explaination, but now that I think about it, the pressure cooker analogy seems to fit better than anything else I can think of at the moment. I sure would like to hear from others on this. I will most likely learn something.

My feeling is that for the Cascades, de-glaciation caused a degree of synchronization between the eruptive phases of nearby volcanoes. The eruptions would have happened anyway, since they are driven mostly by the subduction rate, but the build up of ice mass retarded some eruptions and the subsequent thaw then allowed these eruptions to initiate more closely clustered in time than they would have otherwise, catching up to their eruptive potential in effect. From just visual observation my guess is that Rainier is the only cascade volcano that still carries a really significant mass of ice perched on its upper flanks,(though maybe Baker does too). Rainier’s glaciers are retreating and thinning rather quickly, so maybe the hypothesis that de-glaciation can help uncork a volcano will get tested in the next couple of decades. In Rainier’s case the un-weighting is not just the loss of ice cover, but also the transport of vast amounts of rock in the form of silt and gravel that moves down the river valleys with the melt water.

I’m pretty sure WUWT is just a denialist site. If it involves melting ice, by dogma it must be wrong. I also thought everyone knew about the soda-bottle model in volcanism. BBC Horizon even covered it.

Thank you for your discussion of the science, which is fascinating to this lay reader. However, it is naive to think you can avoid confrontation with the rightwing on issues of climate change. There is no civility possible with global warming deniers and they will ridicule you for merely speculating that global warming might have some slight impact on the rate and kind of volcanic activity that occurs.

I’m sorry to be so blunt about it, but I’ve had much experience with these creeps. You cannot avoid confrontation with them and attempts to do so will only make it that much harder to keep your discipline independent of political interference. If you think that volcanism couldn’t possibly be politicized, I refer you to the bizarre comments on seemingly non-political science (fruit flies, eg) by Sarah Palin, John McCain, and Bobby Jindal for just a few example.

But I’m not a scientist so what do I know? If this issue enters the public discourse, you’ll see, I’m sorry to say.

* If SA is correct, how come Iceland is riddled with tuyas (flat-topped, steep-sided mountains such as Herðubreið http://www.ismennt.is/not/jonasg/0landid/jg01/herdubreid/ ) and volcanoes that show clear signs of having begun life as tuyas, but no fully fledged stratovolcanoes nor shield volcanoes?

* Since pronounced glaciation has the power to lift nearby non-glaciated areas substantially continent-wide at the same time as the glaciated areas are equally depressed, why should the release of that stress induce more volcanism?

In all fairness to anyone interested in what’s happening in Iceland these days, and the impact on Europe, regardless of the website or the comments of those who traditionally visit those sites, the key reason each of us ‘surfs’ is the acquisition of knowledge (or “fun“ -whatever that is). Each website has it’s own ‘personality’, it derives this from its owner and it’s traditional visitors, it takes a while to get accustomed to what the quirks and idiosyncrasies are at each site; and who the pranksters and the knowledgeable folks are. In my limited excursions in the blogosphere I’ve noticed that when people become bored they get off-topic and they tend to get abusive and sarcastic; I tend to get philosophical or humorous. The old saying about not saying anything if we have nothing good to say seems to fit, but we’ve lost a lot in the past 50 years in civility and decency. Haven’t we?…

@tristero (#6). With such an attitude towards those who do not share your beliefs, what do you expect? Change can only come from within, it cannot be coerced. If you believe in the ultimate superiority of your position, prove it to their satisfaction, not yours! And remember to do so with humility, patience and love so that you allow them to retain their dignity.

Melting of glaciers is reducing the pressure in the magma camber. This should increase the possibility of an eruption.
But in this eruption at Eyjafjallajokull the fissure opened first at Fimmvorduhals. It released some pressure. The eruption stopped and after short while started at a place with much higher pressure, because the site at Eyjafjallajokull seems to be about 400 m above the first place. If pressure is the important factor in an eruption it should have continued at the first place.
IMHO the pressure of a glacier cannot prevent an eruption.

I thought the problem was with volatiles triggering explosions rather than decompression melting, too. (It’s another “cause” versus “trigger” problem, I think. Partial melting is ultimately the cause of volcanoes, but the actual eruption can be triggered by something near the surface. The landslide that triggered the 1980 Mt St Helens eruption is the example that always comes to my mind when I think of the relationship between pressure, volatiles, and eruptions.)

In this case, I also wonder about the effects of changing stresses on the rock above the magma chamber. (Removing the weight of the ice might make it less likely for vertical fractures to form, though, especially in a place like Iceland where I presume the greatest principle stress is already vertical. Hmmmm. Thinking out loud here. This would make a good final exam question for structure…)

Global warming causes retreat of ice caps and ice sheets. Can melting glaciers trigger increased volcanic activity? Since 1890 the largest ice cap of Iceland, Vatnajökull, with an area of ∼8000 km2, has been continuously retreating losing about 10% of its mass during last century. Present-day uplift around the ice cap is as high as 25 mm/yr. We evaluate interactions between ongoing glacio-isostasy and current changes to mantle melting and crustal stresses at volcanoes underneath Vatnajökull. The modeling indicates that a substantial volume of new magma, ∼0.014 km3/yr, is produced under Vatnajökull in response to current ice thinning. Ice retreat also induces significant stress changes in the elastic crust that may contribute to high seismicity, unusual focal mechanisms, and unusual magma movements in NW-Vatnajökull.

It looks like this is specific to a single icecap. Unfortunately I can;t read this from home. I also noticed that the article on the Scientific American site is credited to Reuters, not SA, for what it’s worth.

A link between loss of ice cover and volcanic activity seems plausible to me, but I think doug mcl has it right: it would only result in a slight clustering of activity in the short term, by giving volcanoes already poised to erupt a little extra push, without boosting volcanic activity in the long term. Of course, on human timescales that clustering effect could still have a significant impact.

As for the global warming angle, I agree that it can sometime generate more heat than light – although if everyone can agree that the ice sheet in Iceland is shrinking, discussion can (hopefully) focus on the possible physical consequences of that shrinkage, without stepping back into arguments about it’s proximal cause, which are in this case irrelevant.

I should probably also mention that these ideas are based on the observation that there was a clustering of volcanic eruptions associated with deglaciation at the end of the last ice age (see this reference, for example, particularly Figure 6). The geological record therefore supports some sort of link, even if the exact mechanism might be less clearly understood.

While you cite two recent soft-science discussions on post-glacial continental rebound,Google search results (continental rebound post glaciation) clearly shows that there are many quality technical journal publications on the topic worth citing and discussion.

This is not the realm of speculation. It’s hard-core interdisciplinary research topic: glacier mass-balance temporal trends and crustal deformation geophysics that may influence multiple processes underlying volcanic activity and earthquake rupture periodicity and return periods.

Disclaimer: I haven’t had a chance to read the article yet, but it is being mentioned all over the news, so Erik’s reference is timely.
The unloading from small bodies of ice (mountain glaciers and even the relatively small Icelandic icecaps) conceivably could influence the movement of magma already present, but I doubt it would have much, if any, effect on the amount of partial melting down near the crust-mantle boundary.
Now the removal of big ice sheets does produce significant isostatic rebound so in principle that could promote mantle upwelling and melting. But crustal readjustments operate over longer timescales than the advance and retreat of ice sheets, so any influence on melting would not be immediate.
In fact, even in this scenario I still think you would need the standard tectonic settings and conditions for melting. After all, we do not see volcanism in Northern Quebec and Scandanavia, which have undergone significant isostatic rebound since the end of the last glaciation.

I’m not trying to say this isn’t an area of hard research, just that it suddenly has mainstream attention and I offered my take. I’ve talk to quite a few people who study this phenomenon in the Cascades and British Columbia, so I know this problem has been examined for years.

Also, I definitely agree with the idea that this is likely a short-term (geologically speaking) effect – but glacial rebound can takes thousands or tens of thousands of years, so long in terms of human timespans.

@EKoh #16, I think you have more of the right idea of what is going on. You have the expertise. I want to go back to the “pressure cooker” idea and get your take on that. My idea is that if there is enough heat and pressure, would it matter if there was a thick glacier on top? Seems it would blow anyway as we have seen in some of the eruptions under the glaciers that tend to not go through the glacier, but move sideways and spread out under it. Hence the flat top.

It is a very complicated issue as to just what is doing what or what is easing what. Pressure, gases, heat, the crustal depth, the ice cap depth, all figure in here and I can see where a glacial melt may not affect an eruption, or potential eruption, at all. In some cases glacial melt may be affect a particular situation, but in other cases it doesn’t.

Is anyone having luck accessing the cam sites lately? I’m unable to get any of them to work except mulakot. Have been trying the Mila (all three), Vodafone and Katla cams. Mostly timing out, must be bogged down from all the traffic. Hate to miss these views…

We geologists are use to working on wide-range of timescales and I think we often forget that others do not. I think it is one of the major problems we have communicating our findings to the general public. The problem is often made worse when studies are reported in the general news media and the timescale factor is either overly simplified or ignored altogether. We must always emphasize that time cannot be ignored when looking at geology.

Re. Cams, I’ve had little trouble with most of them – except they can be very slow to update. The exceptions are the RUV Katla and Hekla cams, which have been dead for me for 24 hours or so now – sites are up but it never gets to ‘buffering..’ it just sits there saying ‘ready’.

If this topic becomes part of the popular discourse, we’ll see how far humility goes when dealing with the rightwing and other climate change deniers.

Please understand: I am not talking about people who disagree with me. Not at all. I’m talking about people who hate people like me. If you think that’s a paranoid delusion – that people who deny global warming are merely poorly informed, say, – then really, my friend, you haven’t been getting out much.

These are rightwing ideologues, these are extremists. I can assure you, being humble when discussing, say, the invasion of Iraq, and oh-so-many liberals were so very civil and thoughtful, got everyone exactly nowhere. And people died. Many people died. My only regret was that I, who was far from polite, wasn’t more impolite.

But you’ll see. Or if you’re lucky, the impact of climate change on volcanology will continue ride below the radar and you won’t. I hope the latter, but fear the former.

I know that, I have been watching since last evening. It is gone now, but for several frames there was a large amount of activity way to the right of the usual vent (about above the bare triangular outcropping.) It was a different color than either the steam or dark ash, more of a reddish brown. It was in front of the rest of the stuff.

It was kind of like a bomb had gone off above the triangle. I have a screen grab but nowhere to put it that is public.

ICE NEWS today: “AFP reports Sigrun Hreinsdottir, a geophysicist with the University of Iceland, as saying that the lava flow has slowed and that the whole eruption could now slow dramatically as a result.
University of Iceland geophysicist says there are now clear signs that the Eyjafjallajokull volcano, which began erupting on Wednesday, is slowing down. Attention is now turning to the more violent Katla volcano which many fear will erupt next. However, there are no indications that Katla is reawakening at the moment.” ANY COMMENTS?

Doesn’t look like it’s slowing down to me. From the way Ej has behaved in the past “slowing down” isn’t a good thing. This lady is going to do what she is going to do regardless of what we think. Concentrating on the science of what we sense ourselves or with our instruments is key here. Obviously no one can accurately predict how this eruption will unfold. If they could then we wouldn’t be talking. One thing for sure is that volcanoes have a two fold effect on our planet and it’s life. They are the reason life exists and they are the cause of mass extinctions. In between the two they are both beautiful and a pain in the ass. Which one will this be? One thing for absolute sure is that this event is already historic. If this abates, will we learn from our past or repeat our mistakes yet again? We know very little about our recent past as evidenced by the “Theory of the Ice age” and its “climate gate” like data. Maybe this will re-awake the thought process a little bit and we can start to look at things in a new light before it kills us all.

Iceland, ok so why was there a giant eruption in Iceland in 1783 with all the massive Ice during the little Ice Age, and even bigger eruptions in the last 1000 years, many of which supposedly much cooler then today.

Tell me if I have this wrong. In recorded history, Katla does not erupt without Eyjafjallajokull, but Eyjafjallajokull can and has erupted without Katla. The last big eruption of Eyjaf lasted two years. How (if anyone knows) does that eruption compare to this one at this point? Also, from the radar images it looks like 1) The eruption is happening in the center of the caldera, and 2) The craters are getting bigger. Anybody else seeing the same thing?

A favorite blogger of mine, Geotripper, had a quote recently that I’ve taken to heart: “Coincidence is not correlation” So how many “linked” eruptions would it take to be able to say, with certainty, that Eyafjalljokul was linked to Katla?

I seem to remember a geophysicist saying that some one would have to accurately predict 10 consecutive earthquakes before their theory could be used as a tool for prediction.

Richard #43, Katla can erupt by it self and has erupted more frequently then Eyjafjallajökull. But at the few times that Eyjafjallajökull has erupted, 1612 and 1821-1823, there has also been Katla eruptions. You can find info here: http://www.volcano.si.edu/index.cfm
Just type Katla and Eyjafjallajökull in the volcano search field.

OK, a little help help needed here, can someone please explain the science behind the different coloured plumes? am I right in thinking the white clouds are vapour from the icemelt whereas the grey/black is ash?

Am a complete novice when it comes to Volcano’s, I have always had a curisoity for them but never took it anymore than that, am enjoying this one very much with all the live cam footage though.. My vulcan curiosity is growing for sure.

@Richard (#43) sorry but you got that exactly the other way round. Katla has erupted numerous times without Eyjafjallajökull, most recently in 1918 and before in 1860. It’s Eyjafjallajökull whose eruptions seem to be followed – for as little we know – by eruptions in Katla. There seems to be evidence, though, that their magmatic systems are independent. So, in reality, we don’t know. For the moment, Katla shows no unrest. So for the moment she doesn’t seem to be on the verge of erupting. This may change, that is clear. But let’s say in recorded history, one eruption triggering another at a nearby volcano is something rather rare. It would be another haunting and – from the scientific point of view – fascinating facet of this eruption if it were capable of shaking Katla awake. But I hope everybody agrees that all of us should wish this will not happen, because Katla would only add to a mess that is already too big.

@Gordys – I used to believe in these magazines, but the way they spin Climate Change into every possible scenario, I really find those magazines unreadable now and really question a lot of science, I used to believe science pretty blindly, but now I am far more critical. It’s a shame that scientists are jumping on the gravy train to do silly studies just because they will be funded by their political masters.

Iceland is a mantle plume often fissure eruption with spreading of the island at the midaltanitic ridge, this keeps going no matter whats happening above. Sure technically volcanoes can be triggered but glaciation reducing, just like it occurred in Snowball earth. So did we see increased vulcanism in Iceland during the Roman warming, the Medieval Warming? I think some of the biggest eruptions occured during the Little Ice Age contradicting Scientific America’s “theory”.

I think it’s a lot more complex then suggested and a giant mantle plume really doesn’t care if a tiny glacier has moved forward a backward a little bit. Maybe if we had a 14m sea level change and a sudden deglaciation as well we’d see something happen, but the current changes are so small, fractions of degrees. The winter in the arctic has been quite cold this year, so why didn’t that stop the eruption then, because the glacier might have increased over winter lol?

Another interesting point to be made is that spread of the volcanic ash gives us information. The fact that the ash is doing the europe rounds instead of the polar northwards rounds suggests that europe’s summer will be a warm one. When the current heads to europe, the summer will be warm, if the current goes to the pole, europe will be cool. Europe’s temperature/weather is determined by this current not voodoo science

We just might be able to predict events like this one, and ones to come if we would just fund the magnificent dedicated individuals who have dedicated their lives to saving ours. Our money goes not to their cause but to our own destruction. As Alli posted earlier, maybe we need to wake up. We need to know more about these things…now! No nuclear power can match the destructiveness of volcanoes. We have to be proactive, not reactive. I wonder if 1 trillion in USD would help? A bailout for science. Now that I would gladly accept.

You are right parclair. We don´t know how strongly related they are. Those two historical eruptions indicate that there might be a connection, but those two eruptions might have been the exeption from the normal behaviour. So we can not tell how large the possebility for a Katla eruption is.
I won´t worry about it so much as long as instrument doesn´t detect any significant disturbence at Katla.

Mattias and Boris – Thank you for the information. I was not aware of this. The information I had was from statements made to the contrary. I think this was the common thinking as it has been on the web and the news channels. They are definitely linked as they are part of the mid Atlantic ridge. I think the conclusion is that they are independent. It makes sense but as we are seeing, history is in the making and only time will tell. I do hope that this will only be a “wake up” call and it will not intensify. I feel that I am wrong though as there are no indications of it lessening and every indication of it strengthening. I wish I could see some updated radar images of the craters, it would definitely shed some light. Also, I had at one time a link to a site that showed tremors indicating magma movement. I can’t find it now. Anybody have any idea what I am talking about and a link to the site? Thanks to all for the information and the corrections. It is greatly appreciated.

re: Cause vs Trigger
The Great Lakes have rebounded what? About a Mile since the Ice Sheets withdrew, and there arent any volcanos in Michigan just right now.
Merely lowering the pressure by itself doesnt seem to be sufficient Cause.
OTOH, the big eruption of Mt St Helens was triggered by the landslide (or the landslide was started by the eruption?) so overburden seems to play a role.
I’d venture that a system that was on the cusp of erupting will have the timing advanced or delayed, depending on whatever is above it at any given time.

re: Cause vs Trigger. The Great Lakes have rebounded what? About a Mile since the Ice Sheets withdrew, and there arent any volcanos in Michigan just right now.

There seems to be a confusion here I’ve noticed further up in the comments: at least as I understand it, this is about the effect on the (shallow) magma chambers and plumbing of pre-existing volcanoes, which might be sensitive to (relatively) small changes in pressure. It is not about creating new volcanoes in regions with no previous activity. Volcanoes would exist on Iceland with or without any ice sheets, but its possible that the waxing and waning of the glaciers could modulate their activity somewhat.

Diane, I think this is the same one we’ve seen over the last few days. A few times when it was cloudy, I thought I saw intrusions of ash into the scene. II had no idea the vent was so close to the camera until today.

There is a new radar image posted here along with some great picture and videos! I think it is safe to say that the craters are getting larger and are apparently joining together. It is getting larger and more intense as time goes by. It seems that way to me anyhow. I hope I’m wrong but it doesn’t look that way.

Who is Magnus Tumi Gudmundsson? I saw his name on Fox News and on a statement he made earlier about the first event being over a while back. This time he says, on Fox News, that the explosions are due to the water in the volcano. I don’t think that this is quite true and seems to imply that when the water runs out the eruptions will lessen. We have no way of knowing that do we?

Not to try and rudely dispute him but we need the truth here not just speculation right? The best experts on this subject can be found here and in groups like this one. At least you guys take the time to show up. (not that he doesn’t)

Would any of you guys care to say that this thing is intensifying? I think it is obvious to even someone as dense as myself but it would go a long way to hear an honest opinion from the professionals. Are you guys (and gals) worried?

I believe at this point Ej is the “hottest” volcano on the earth right now isn’t it?

Thanks everybody. It is really something to watch all that power. Scary,too. I still am wondering, but that is ok. We will know soon enough if there has been another crater opening. I kind of doubt it at this time, but it could be. Regardless, it is awesome!

Valahnuk will get interesting if that thing starts to move down the slope.
Exactly where is that webcam? Is it up on the mountain, a few km east of the caldera? Or is it on the south east side of the mountain?

The harmonic tremor now show clearly up on my seismometer, as there is almost no wind (0.4m/s) where I have my seismometer. The reason why the line is thick is because of the volcano eruption in Eyjafjallajökull.

I do not know exactly how long this calm in the wind is going to last. But while it is, the signal is coming trough clearly.

Hmm. After comparing with fimmvorduhalsi I have a feeling that valahnok is looking up the Gigjökull on the north side of the volcano. But I still cannot place it exactly. Is Gigjökull to the right or to the left of valahnok cam?

@StarBP. Since the peak of Eyjafjall is at 1,666m, the ash plumes can be not much higher than 5,000m asl (above sea level), about 3,000m or 10,000 foot high above the mountain today.

Maybe ash particles can be found at the level quoted, but I very much doubt the plumes ever reached that high. I seem to recall a figure of 8,000-9,000m (27,000 – 30,000 feet) but don’t recall if that was asl or above the peak.

Okay, the plume seems to be a constant ejection of pure ash at the moment – almost no white, almost solid black. At least from the Valahnúk perspective. Hvolsvelli shows a few white patches, but there’s a lot more ash going up a lot more consistently.

#85 StarBP: “How high are the ash plumes? The site #76 linked me to says 55,000 feet (16 km)… is it really that high?”

55,000 feet sound to much in my opinion. At this moment I think its about 6-8 km when it´s pulsating, but I cannot say for sure. Occationally there might be 10 km, but I doub´t it.
Btw, I couldn´t find the numbers in that link.

@ Austin. What I meant to say was: At dawn, the eruption looked all dark, with white patches. On the Valahnjuk cam, the actual eruption looked white, while the spin-off looked dark. Then, as the sun came up, it merged into the day-time shadings. (My employees always had to remind me that “mind reader” was not in their duty statement;)

Have you noticed the lightning on thorolfsfelli as well as valahnjuk? whoo hoo!

I’m going to shoot my mouth off just a little here (sorry if I’m out of line here Erik but I think it’s worth saying) and give a warning: I’ve been on other bulletin boards and discussion fora (where ‘experts’, both real and self-proclaimed discussed the topic at hand) while newsworthy events were taking place, and observed people who were believed to be journalists making inflammatory comments and asking loaded questions in the hopes of getting ‘something’ they could use and write about.

I would most gently suggest that folks here don’t pretend to more knowledge of geology than they have, or be quick to make predictions on incomplete data which they may not fully understand – lest they find themselves appearing (attributed or otherwise) as ‘an expert has said…’ in the press the next day by some lazy journalist desperate for an ‘angle’, a quote, or some invented sensation. It has happened before elsewhere. Anyone can read, and post, here.

This suggestion is a general one and is NOT, most emphatically not, directed at any individual.

Interesting. I caught a webcam image with a bright sky but with no lightning flash visible. The plume was still dark so I figured that the lightning must be behind the plum. After downloading it I can suddenly see the lightning flash, strange. http://i43.tinypic.com/w9irmg.jpg

@Zander, thanks for answering Frito Lay’s question. Every (my) night at (Iceland’s) dawn, I figure out the directions of the cams. By morning, all is forgotten;-( Now I’ve got a map to which to refer.;-)

Re Greg’s comment #36 about Sigrun Hreinsdottir saying the eruption is slowing, it’s hard to know what Ms Hreinsdottir actually thinks, as she’s being reported as saying contradictory things. It may be that she has changed her mind, or journalist are misunderstanding or misrepresenting her, or she has been too vague in her communications thus creating confusion.

‘AFP reports Sigrun Hreinsdottir, a geophysicist with the University of Iceland, as saying that the lava flow has slowed and that the whole eruption could now slow dramatically as a result.

‘Hreinsdottir says it appears the lava is flowing from a lava chamber one kilometre deep. She likens the lava chamber to a bursting balloon, adding that nobody knows how much lava is inside in order to accurately predict when the eruption will stop fully.’

‘Volcanic eruptions may continue for months, curtailing European air traffic when the ash reaches the region, said Sigrun Hreinsdottir, a geophysicist at the University of Iceland in Reykjavik. “From what we’ve seen, it could erupt, pause for a few weeks, and then possibly erupt again.”’

Personally, I think it’s irresponsible of anyone to report that the eruption is ending, because there’s just no way of knowing. And certainly as the sun set in Iceland this evening it didn’t look like it was letting up. Lots of people are waiting for this eruption to end so that air travel will resume, and giving them what might be false hope is not just mean it also might mean people making poor decisions through wishful thinking.

As far as I can tell, we really haven’t a clue how long this is going to go on for. Saying it’s winding down seems to me to be very premature.

(was on holiday in Iceland not far from the volcano last week, so following with interest what’s happening on this blog, already before I left, nobody of the people with me was believing this would happen …)

If we see one Hz level rise as opposed to another, is this indicative of water intrusion such as a chunk of glacier giving way and falling into the crater, or a fresh magma intrusion, inflation/deflation or what?

It seems as though there are times when the 0.5-1 Hz levels stay low while the 1-2 Hz and 2-4 Hz levels rise, and sometimes the other way around, and sometimes they all rise. Also, the differences between each monitor and which Hz level is the strongest are quite striking.

It’s unfortunate it was cloudy during 18:00 on the 15th when the tremor was going crazy…we couldn’t see what the volcano was doing.

The world has too many “journalists” and not enough reporters. Anyone can be a “journalist”, it just means you write things down. And “journalists” can be very … uhm … artistic, in what they write down.

@120 Suw found this information: ‘Hreinsdottir says it appears the lava is flowing from a lava chamber one kilometre deep.’
How has she determined this?
Can geophysicists extract triangualation information from tremor data?

@Fireman
It makes no difference what you say as the journalists are only interested in doom and gloom so what you don’t say they will make up and lets face it, we really don’t have a clue what she will do next!!!

The definition of an expert is…
“X is an unknown quantity and sPERT is a drip under pressure…”

and from what I’ve seen coming from some of the media reports, that appears to be partially true in some cases…

Thanks Benjamin, that was great! If you have time to make more of those time laps movies, don´t hesitate. It would be great to have a automatic function in the webcams that make this kind of movies. Lets say that a new movie were to be published every 6 hours or so, and then it would be possible to access or download it.

I have to say , if i lived in the houses on the hvolsvelli cam i don’t think i’d see the inside of those houses for days.I don’t think i could drag myself away I feel lucky to see this real time. 20 years ago this wouldn’t happen.

From a complete novice who was found this site just because she’s trying to figure out when the airports might open….

Thank you to everyone on this site for all you are doing to educate and help me enjoy this story. The comments are informative (and are expanding my vocabulary!) The great links to photos, the time-lapse videos which make my inability to connect for most of the day bearable, and the summary of links page all deserve a special nod.

I understand only a small portion of what I’m reading and seeing, but your enthusiasm and willingness to share has kept me interested and stretching my mind to understand more of what you are saying.

I find this eruption awe-inspiring and as it has been stated many times over the last few days, it is a little one. So this is mind-blowing for me as well as inspiring!

@Dylan et al,
Strange about that red light. Scratch what I said earlier. I was trying to reconcile it what I had seen in the daylight but something that low doesn’t make sense unless, as Reynir says, it’s a reflection of some sort.

Just received this e-mail from Pétur at Vodafone and felt it would be of interest to others:

“Hello and thank you for showing an interest in our webcam.

Earlier today, we had to close all traffic from abroad to our web server, since load was too heavy, and we desperately wanted, and needed, to continue to give our Icelandic audience access to the images.

We are working on methods that we can continue to bring the images to a worldwide audience, but for the time being you will be able to view images in a public gallery that we created with the help of a company called Google!

Apologies for these drastic measures, we hope to be able to open the webcam to the world in some way or another soon.

@Kate 160. Welcome! …”trying to figure out when the airports might open….”
What I’ve learnt is that the experts, and there’s a handful here, dont know when the eruption will moderate or end.
Might be more useful to look at wind forecasts. Try:http://en.vedur.is/weather/forecasts/elements/

Vodaphone needs to find a mirror site to take the load off their server. Local universities are one option, but there is a much better one – talk to Google.com, whom I’m sure would happily provide plenty of bandwidth if a commercial rights deal can be struck.

I really hate nite time in iceland. I have been watching this site since the first eruption..geology is my secret passion. I get really frustrated not being able to actually see the activity like during the day. Thank you to all who post their information for the benefit of all.

renee, if it is any consolation, Iceland is about halfway through it’s night. It will be getting light there in a couple of hours. Also, the moon will be increasing and rising earlier over the next several days so we will get some moonlight in about a week.

I was watching Weather Channel (which has had decent-for-media coverage of the eruption) and they were talking to travelers and travel agents stateside who were looking at southern connections (ie southern Europe). No word if there was any luck—

If you are reading this from an airport, find some other way to get home. Just assume that the airports in the UK are not going to reopen (already announcing massive layoffs.) Even if it were safe to fly, we are likely past the financial tipping point for many of the domestic airlines. They were not in good shape to begin with.

KLM is really pressuring the Dutch to reopen their airspace, but I would not want to be one of the first to fly in it.

Aren’t there prop ‘regional hopper’ flights working out of most regional airports?

Can they be used to ferry waiting passengers in and out of closed airports to southern regional air centers that are open?

It seems like a do-able plan, as the skies are relatively quiet in the affected areas. Southern regional air centers are going to have make accomodations to land these flights at smaller air ports outside of the open regional centers, to funnel passengers in, who then wait for extra flights to be scheduled.

Ask any volcanologist: you can’t plan for an eruption to stop. Given the relatively slow movement of the high pressure mass, you face airport closures for several more days, minimum.

You need Plan B, so you might consider what I’ve suggested as an alternative to playing Wait and See.

Neither the weather nor our Eyjaf can be expected to cooperate in the next day or so.

@Scott, More activity on the IMO tremor plots means more is happening in the volcano. But what we do not know for now due to darkness. There is going to be 24 hour daylight from mid May. I am expecting the eruption to be active by then.

In the darkness the lightning mark the ash plume and how big it is. Given that, it looks big and dark.

As I understand it, the vast majority of those are turbo-props which are just as vulnerable a turbo-jets. Those with old-style prop engines (like a car engine) are mainly as small as the planes we see flying about the volcano today. Even these need to regularly clean their air-intake filters.

this is pure speculation however here goes Þórólfsfelli and Valahnúk look at the same area from different locations just above the outlet of the glacier, the lightning on Þórólfsfelli is almost off screen to the right to say going into the outlet trough of the glacier ‘ Valahnúk the lightning is lower and closer to center ie in the trough
could the fissure be opening in to the trough or the river valley below it again pure speculation based on memory from daylight observations

For once, I’m home (over a year there is only a 50/50 chance of that being true and Northern Europe is our most frequent destination.)

We have many friends stuck but all that we know of are safe and are working their way back home slowly. The most dire is my friend working her way from Belgium to Ireland to hold her baby again – it was only to be an overnight trip and the papa is in North America. But the baby is safe with grandparents and mama has a passage on a ferry on Tuesday if airspace doesn’t open sooner.

Our next trip is Thursday but not off North America although we may end up losing money since some of those students are from overseas. Trondheim in Norway is end of May was my next European trip and I suspect will be canceled due to low enrollment as people shy from unnecessary travel over the next while. Coming on the heels of the economic downturn, it is rough on us, we’ve just started working regularly after 9 months of nothing.

But I’m sure it will be much rougher on many more people. Our biggest, immediate, issue is that our European partner can’t courier us material for trade show. Small scale stuff compared to shutting down a production line because of lack of stock, or grocery stores running out of fresh produce.

The eruption has not stopped, is getting larger and stronger, and will continue for an unknown time.

It is not safe to fly anywhere near the ash as damage can occur without even seeing the cloud.

This is a first for mankind in the way it effects air travel. There are bound to be other firsts as our “technology” makes contact with this new menace. It has happened before but not with modern society.

If the eruption continues and the winds stay their course this will soon have an effect on North America as well.

The eruption of 1783 had an enormous effect on mankind because it was larger. This will, for now, at least have a lesser effect on us as well.

Check this out. It is from a book called “Animal Plagues.” It describes the 1783 aftermath in some pretty clarifying detail.

Go to page #509 for the online version. I found it easier to download the whole book (it’s free, imagine that) through a link there. It’s page #546 in the PDF version. It’s easier to read and the book has allowed me to correlate some diseases (fluorosis for one)and famines with catastrophes. Scary stuff.

There are no indications that this is going to happen on this scale but it is helpful to know what effects an event like this could have.

We are not ready for this and as it has already been pointed out we should be. I have heard that through biological processes that farmers have to purchase their seeds each year instead of getting them the natural way. If this is true the modern world over, we are in for trouble. Think of the implications 2 years from now.

I’m not trying to start anything for the “journalists” but we are not being proactive, we are being reactive.

This is not going away. There is no reset button this time.

We are going to need all of the intellectual minds we can find to combat and possibly overcome a large event. For now we do not know how big this could become. There is nothing wrong with being prepared.

Here is a pic of one of the pranksters at Þórólfsfelli taken about 45 minutes ago (had trouble posting here). There were better shots of someone else but my fingers weren’t fast enough. I’m sure I would have done the same thing if I had the chance when I was 17.

The whole event is truly fascinating. I wish I knew more about volcanoes, always thought they’re awesome (to a certain degree before they get scary!). Thank you Erik, and the other experts who put their input on this blog, it is better than reading the news because it is more factual here. From my very,very limited knowledge, is it true the eruption of Eyjaf will be nothing compared to the eruption of either Hekla or Katla?

Although there was limited small prop plane traffic allowed at low altitude yesterday, a check with pilot friends said that electronic instrument damage was a major liability, even if engine damage could be avoided in a turboprop/turbofan.

There is some information on what a team of researchers from New Mexico Tech are doing to monitor the lightening. They have deployed a six-station lightning mapping array around the Eyjafjallajokull volcano.
See the spaceweather.com site

Someone asked this earlier but I don’t think I saw a response. Is current seismicity typical for Iceland? Or at least typical for this kind of eruption? I just noticed the earthquake map at Iceland Met light up with red dots and I don’t recall seeing so many at once since I started watching.

Possible mechanism to cause Katla to erupt. Could dark ash falling on the Katla ice cap absorbs sunlight causes melting leading to eruption? Am not sure if this could happen in the required time frame. Or could the simple increased melt water from the top of the ice trickling down do it?

“All around us, it was as if the universe were holding its breath, waiting. All of life can be broken down into moments of transition or moments .. of revelation. This had the feeling of both.”
Babylon 5

Larry, given that Katla is under nearly 800 feet of ice, I don’t think a little ash on the surface is going to matter. In fact, if it is think enough, it can act as an insulating layer.

What is likely to have a larger impact is the venting of material allows material deeper below to rise up. This brings hotter material up which can cause melting of some more evolved material that is just barely at the melting point. I suppose that would make it possible for segments of the system to reactivate but it would be pure speculation to say that is what is happening.

@Diane, I remember those kinds of anomalies, too. I’m going to wait and see on Redoubt. It’s still at level green. (There is nothing more fruitless than waiting for the skies to clear on an Alaska webcam.)

Unless it is waiting for the weather to clear at Eyjaf, LOL. It could be that they have not been watching 24/7 right now as they were during the eruption. But they are two hours behind CA so maybe there is somebody watching.

Since we can’t see any lightning anymore and since the weather forecasts for southern Iceland predicts 1 mm of rain for the next 3 hours – I guess the clouds have already come in and obscure clear sights of the eruption.

Both summit stations at Redoubut show the event @1830, so it isn’t somebody stepping on the recorder unless they are really close. Other than that I do not know how to judge if it is seismic or something like a rockfall/avalanche nearby.

77: I have occasionally looked at the comments on “eruptions”, and there is an expressed opinion that the current eruptive character is caused by large volumes of glacially derived water mixing with the magma. So the theory that the character of the eruption will soon change when the ice/water supply is used up, seems like a perfectly reasonable thing to say. If that proves to be the case this would affect the amount and type of ash produced and how high it was injected into the atmosphere. This could be important, as the eruption could continue for many weeks, but perhaps the ash risk to airplanes will diminish.

As for tristero: I think we have two major types of denialist types to deal with. Clearly we have those you describe, who are driven wholly by politics, to them anyone supporting any theory they find distasteful is an enemy combatant. But, there is probably a larger audience who isn’t primarily driven by ideology, and they may still be reachable. So your warning should be heeded, scientists will be attacked because of their data/theories regardless of the motive for producing/publicising it. OTOH, we need to be seen as the reasonable party in order to have some hope of reaching those whose minds are not closed.

Why is it that station GOD (Godaland?) appears to have 5dB greater seismic coupling to the eruption than station ESK (and 2.29dB greater than MID) even though it is further away than those two stations?

Setting the scaling equal on the traces on hraun.vedur.is/ja/Katla2009/gosplott.html and measuring the amplitude of the five most noticeable spikes for the last 24 hours show something going that the station on Hekla has better coupling to. (sees it better)

@281: Although the possibility that tremors are stronger on that side of the volcano exists, you have to keep in mind that the values for this type of tremor calculation don’t really have a real unit of measure and therefore aren’t directly comparable between different stations.

I noticed something like that, too, earlier. Station hvo had a trace from about 0900 16APR to about 1700 17APR that was not very closely coupled to the trace at the god station. Then, suddenly, the response from hvo appears very close in patter to god.

It could be a lot of things, some of which might be local to where the telemeter is located. But it was noticed and it is “interesting”.

At my current level of understanding, if a vulcanologist described the ongoing eruption as “A sustained andesitic, sub-glcial, phreatomagmatic, sub-plinian VEI 3 eruption nosing its way into the VEI 4 range”, I would understand perfectly.

Just wanted to say how fascinated I have been with your blog. I am a resident of Australia and have found your links very helpful. I have to agree with a number of your comments – it does appear to be snowing. What effect could this have on the future developments of this intriguing volcano?

Seems to show the plume as a cold band, presumably as the high altitude particles are colder than the surface.

Modis is a good resource to get pictures once or twice daily (“real time”).

NB You have the blog of the moment and deserve credit for a rational discussion (removing flames and spams too, I hope).

I am not too sure global warming adds much as a topic, it is indisputable that this has been going on since the turn of the last ice age.

I am intrigued by the suggestion that hot deep magma might rise to ‘fill the gap’ thus causing a remelting of lower melting point rock above. I wonder if a brief discussion about this is on topic? I remember a Scientific American article of many years ago where only 100C or so could have dramatic effects on the amount melted and thus its buoyancy with fairly dramatic effects.

NBB I am a complete geo-novice, but interested.

NBBB I don’t think I will be going on holiday from UK to Turkey this weekend.

The weather forecast is W-ly winds today, turning towards N tonight. Looks like the you’ll only get glimpses of the volcano today. Should give you a few minutes to check out Redoubt and the other volcanoes in the world. :-þ

I’m pretty sure WUWT is just a denialist site. If it involves melting ice, by dogma it must be wrong. I also thought everyone knew about the soda-bottle model in volcanism. BBC Horizon even covered it.

Posted by: eddie | April 17, 2010 12:42 PM

You are wrong eddie.
We take a subject and discuss it.
Based on facts.

We now see The Global Warming crowd jump on this Volcano eruptions to sell their nonsense.

If ice play’s such a big role, why did one of the biggest eruptions
in Iceland took place during the Little Ice Age.

If the weight of the ice column play’s a role, how is it possible to have volcano’s erupting many miles under the ocean surface!

You see, you don’t need to be a climate camp of warmist or skeptic, to use your brain!

And about WUWT, this is one of the few sites on the web where people can post their opinion or insights without the risk for sensor ship. So if you have something serious to say beyond your “hollow remark” you can do that at WUWT and I am very confident some of the posters their will tell you if you are right or wrong.

@R. de Haan: You get an eruption wherever and whenever magma breaks through the crust. How great an effect pulling a 1000-foot thick ice cap off has… it depends on how long till Sunday and the latest Elvis sightings.

I’m all for investigating causal relationships no matter how far-fetched they may seem at a first glance. However, in order to even look at such a proposal, some sort of hard evidence clearly suggesting such a relationship must be presented. Furthermore, I resent being dismissed as “denialist”, “right/left-wing”, abasing myself to ad-hominem attacks and suchlike when I do not attach much value to the unsubstantiated beliefs of another. I value the scientific process as described by Popper – in order to be scientific, a hypothesis must lend itself to falsification. If by its very nature it cannot be falsified, it does not belong to the realm of science but rather to those of spititualism and religion.

Unfortunately, science no longer pays homage to abstract and absolute truths. Vile politics have entered it disguised in a psuedo-scientific mantle of righteousness. I’m afraid that my own field linguistics is to be blamed for much of it as they accepted the failed mathematician Noam Chomsky with his reliance upon intospection as “scientific proof” for his theories based upon the totally unscientific bible of grammatics into their fold.

Fortunately, this pseudo-scientificism immidiately reveals itself by drawing inferences to and from human affairs, which is easily seen as the main interest of the “examination” or “paper”, rather than ending with the theoretical implications for further studies to determine.

‘KLM carried out the test flight above Dutch airspace Saturday. It said initial inspections afterward showed no damage or irregularities from the ash in the air that has led to a ban on air travel over much of Europe since Friday.

‘The airline says it now plans to return seven airplanes without passengers to Amsterdam from Duesseldorf Sunday.’

Whilst I think it’s wise to keep an eye on the ash situation locally, I am a bit worried that the airlines seem to be implying that it’s all a big fuss over nothing, which it really isn’t. I’ve already seen people on Twitter saying that they are making a mountain out of a molehill.

I’m also worried that if the airlines start flying prematurely, whilst they may not lose a plane they may wind up damaging them so much that after a while they become unfit to fly at all. So, do we want to be grounded now because of ash, or grounded later because the aircraft are unflyable? I know which option I’d take.

Currently the harmonic tremors are rising fast. There have also been news about the plume, and that it has not reached 3km altitude from 08:00 UTC. But that is a strange one, given the growing harmonic tremor in Eyjafjallajökull.

@Suw 297 – spot-on. I’m seeing some worrying comments in the UK press to the effect that ‘it’s not that bad, they’re being far too cautious, they could get some flights running if they really wanted to’. Not good. This is interesting:

@Fireman Yes, I saw the pictures from the Finnish Hornets. And these were planes that didn’t even realise they were flying through ash! I don’t know what kind of inspection KLM and Lufthansa are doing, whether they use a boroscope or were just doing visual inspections.

@henrik Again, I agree. It’s human nature to take the short view. And that’s why we’re in the collective mess we’re in. *sigh*

But the chatter on Twitter is mostly fuelled by frustration, I suspect. And that’s understandable, but still, not very helpful.

@Mr. Moho, this is not due to weather on the IMO sensors. There is minor weather and cultural noise on my sensor. But this is just the volcano. What is is doing is a good question. But I have big worries at the moment.

Wind from a different direction today, eruption just and just visible(?) below regular cloud occasionally on the Hvolsvelli cam), snow and not much else on Valahnúk cam, Thorolfsfelli offline and Vodafone unavailable.

Is it not possible that ice cap melting an south pole could effect tectonic activity? (EQ & volcanic activity)
Given the mass dissplacement upon that plate and the dispersal to others?
Pressure differentials.

Oh my god: Tremors increased so much from saturday to sunday night and since 6pm (GMT): It seems that the eruption will continue on a very high level. If Jon Friman has big worries, I have big worries too!

Its inevitable that the longer these Airspace restrictions go on, the more the Airlines want to impose their influence on the CAA/NATS/Eurocontrol to start resuming flights again for Profitability.
One shouldn’t forget however the Abrasive and Corrosive effects Ash has on components (even in nearly-diluted form.) Infact it only takes one small crack in a Engine Turbine or the numerous component Blades to completely warrant a overhaul of that engine, thus again having a knock-on effect for all the services that plane was due to operate.

And if 12,000 aircraft routinely fly through the same Plume daily (assuming this eruption lasts for weeks) you can imagine the logistical nightmare. Infact the vast majority of airlines will crash simply because they wont be able to afford the Maintenance. Its a lose-lose situation.

There is a great increase at all frequencies, yes. Jón’s geophones are showing a slight increase in harmonic strength. Visually, nothing (big at least) seems to be going on. Is this a winding up for something bigger than we’ve seen before?

Thanks for the heads-up Shelly! Mostly steam and little fragmented material, weak activity. Also, you can see that it has snowed recently. The tremor is still increasing, so there is obviously a temporary blockage. Keep watching and reporting!

In the absense of experts, I’ll repeat what some of those in the know said yesterday – water from the melting glacier cascades into the crater and vents where it is instantly turned to steam. If the conditions are right (I guess that means magma/lava fountaning or a large chunk of ice falling into the crater/vent), a lot of fragmented lava is ejected too as “ash” and you get a very dark ash column/cloud. IIRC

12.50 GMT, small pebbles(?) shooting at the Valahnúk camera. Eruption seems to be intensifying with bigger clouds reaching higher before being blown off to the left. Impossible to judge colour of column – grey, greyish white or white. Not black though.

What I’ve read of the KLM and Lufthansa flights is that they are low altitude, visual flight rules operations. These kind of flights might help the airlines reposition aircraft in anticipation of being allowed to restart normal operations, as KLM said. But you can’t compress 15,000 planes into a much smaller VFR altitude range, that is asking for a collision.
I’m guessing a lot of trans-atlantic travel is going to get rerouted through Madrid, and travel inside Europe will shift to ground based transport or city-hoppers flying under the cloud.

According to the news on Rúv scientists are currently flying over the eruption site in order to try figure out what is going on at the moment. But it looks like that they are quite at loss what is currently happening in Eyjafjallajökull, as this normally does not happen with Icelandic volcano.

Over the past ~80 years (when volcano monitoring started for real in Iceland) when a volcano eruption starts in Iceland it starts big and drops after that. It does not start small and then grows in size like has happened now.

I am now expecting a more explosive eruption to start soon if there is any explosive magma over there. But that is what I am expecting, given the current data that I have. But only time is going to tell how right or wrong I am in this matter.

What little I have seen thus far of the eruption today indicates it’s still going but somewhat less intense than yesterday. Obviously it may well happen that as soon as this post is placed, the eruption will gain in strength so keep an eye on it, given it’s currently visible at Valahnúk

I would like to appeal to everyone here not to overestimate the size of this eruption thus far – it’s big but it’s not a gigantic eruption. A brand-new report at Nordvulk (www.earthice.hi.is/page/ies_Eyjafjallajokull_eruption) gives the volume of uncompacted tephra (all loose volcanic material such as ash) produced since 14 April as 140 million cubic meters. That corresponds to about 70-80 million cubic meters of dense rock, and it is a significant volume. Put this in relationship with something really cataclysmic like Pinatubo (1991), though, which emitted at least 5 cubic kilometers (that is 5000 million cubic meters) of tephra, then you get a perspective. But right, it may still go there. Let’s hope it will not.

Another note on those among the commentators here who appear to know things better than the volcanologists – you certainly don’t know things better firstly because you don’t have the instruments and you don’t have the experience, both of which are fundamental. Thirdly, you don’t have the responsability to deal with the public, authorities, and divil defense. That’s a very delicate field, where it is of no use crying out your impressions too loudly because they might have strongly adverse effects. Therefore the volcanologists in Iceland are doing their work maintaining a low profile and not spending too much time speculating publicly, but they’ve got some big challenges to meet. So if you read on a news web site that a volcanologist says the eruption is fading, it most likely is doing so. If the same volcanologist says the eruption might continue for some time there is no contradiction there.

Someone (#77) was wondering who Magnús Tumi Guðmundsson is and was skeptical about him saying the right things about magma-glacier/water interactions. I fully agree that the eruption has so far been dominated by magma-water/glacier interaction, it is actually one of the finest examples of a Surtseyan-type eruption, because it does have a lot in common with the early stages of Surtsey (1963-1964).

Magnús Tumi Guðmundsson is actually one of Iceland’s foremost volcano experts and in particular he’s specialized on volcano-glacier interactions. His web profile is here, http://www.raunvis.hi.is/~mtg/ – hopefully this will be enough to make everybody understand there’s little doubt about the authority and professionality of this scientist.

@Jón
that implies that the remelting of existing stores of modified magma is the driver with a adequate supply of basalt being supplied continuously to continue the melting/ejecting and ice melt contributing to the explosive activity
or am i just guessing?

I think the video from yesterday which I posted above shows that the ash didn’t reach a big height initially, I guess this could also mean it is not as threatening to aircraft as it was before when it reached a greater height?

Sorry to go OT, but can anyone here educate me as to why flying through an ultra-fine volcanic ash cloud should be any different from flying though an airborne ultra-fine sand cloud? I have a perception that airlines must be doing the latter all the time…or is this perception incorrect?

@341: “What I’ve read of the KLM and Lufthansa flights is that they are low altitude, visual flight rules operations. These kind of flights might help the airlines reposition aircraft in anticipation of being allowed to restart normal operations, as KLM said. But you can’t compress 15,000 planes into a much smaller VFR altitude range, that is asking for a collision.”

@Helen Leggatt, I have not seen this on the Rúv web page yet. But it was on the radio news.

@Boris Behncke, the magma that comes from Eyjafjallajökull looks rather gas rich, and rich in water (?). So this might well be explosive eruption on it’s own. But I am sure that the water and the ice does not help in this manner. At the moment there is a interesting drop in explosive activity. But we will see what happens soon. As the harmonic tremors have and are increasing at this moment. There is a bit drop now and then. But in general it is increasing slowly.

The outlook however is not good in my opinion, and this volcano is far from being done with its eruption phase.

re356
1 the ash melts and is rather corrosive in engines and may cause failure
2 the ash is not filtered out of the air that is refrigerated (air conditioning) and gets circulated in the electronics for cooling
3 it is conductive!!! it can trash the flight control computers in all fly by wire aircraft (most newer transports)

re351 it looks like a reflection off a shielding enclosure similar to the one on the web cam at the Halemaʻumaʻu from HVO, Kīlauea Volcano when daylight comes there

Eruption of Eyjafjallajökull 17.4. Photographer Baldvin Hansson
This morning was the change in the eruption in Eyjafjallajökull. TF-Sif, Coast Guard aircraft, is on its way to gosstöðvanna to investigate the matter. Measuring service saw the turmoil of gosstöðvunum had increased and ash cloud was seen no longer the radar. According Agust Gunnar Gylfason manager in coordinating civil defense center, this is a sign of change but is too early to say what they are. That will probably occur when the TF-Sif comes back to Reykjavik. Decreased with ash falling in the morning and it stopped at several farms under Eyjafjöllum. That will probably turn to the southeast and east is taking over the day. It is likely then to be in Volcanic Ash Skaptartongue and include land and possibly in Kirkjubaejarklaustur and Mýrdalssandi. We eftirlitsflug Gígjökul views of scientists saw the open channel that leads down from the crater to mount root and running water in it. It is assumed that no accumulation of water in the crater and no significant reason to worry about the run. Farmers have received assistance björgunarsveitarmanna to bring their animals into the house, you are trying to bring horses in hagabeit out of the area.

#361.. Here is the translation… Change in eruption in Eyjafjallajökull

Eruption of Eyjafjallajökull 17.4. Photographer Baldvin Hansson morning was a change in eruption in Eyjafjallajökull. TF-Sif, Coast Guard aircraft, is on its way to gosstöðvanna to investigate the matter. Measuring service saw the turmoil of gosstöðvunum had increased and ash cloud was seen no longer the radar. According Agust Gunnar Gylfason manager in coordinating civil defense center, this is a sign of change but is too early to say what they are. That will probably occur when the TF-Sif comes back to Reykjavik. Decreased with ash falling in the morning and it stopped at several farms under Eyjafjöllum. That will probably turn to the east and southeast is taking over the day. It is likely then to be in Volcanic Ash Skaptartongue and include land and possibly in Kirkjubaejarklaustur and Mýrdalssandi. We eftirlitsflug Gígjökul views of scientists saw the open channel that leads down from the crater to mount root and running water in it. It is assumed that no accumulation of water in the crater and no significant reason to worry about the run. Farmers have received assistance björgunarsveitarmanna to bring their animals into the house, you are trying to bring horses in hagabeit out of the area.

There are so many knowledgeable people around, so perhaps someone can answer my stupid question. What is the main difference (composition, size) between the ash particles which are emitted now and the Saharan sand which sometimes is blown in over central Europe? There must be a reason why the latter usually does not interfere with air traffic.

@boris #350 I don’t think anyone here is saying that they know better or best – people are discussing what information is in the public domain to the best of their ability and in doing so we are, in general, reaching a better level of understanding of what’s going on (each according to their own interest, of course).

Pointing out contradictory reports is simply to say that either the scientist gave contradictory information or that journalists are interpreting it contradictory ways. Neither of those possibilities are good for the public understanding of this eruptive event.

Furthermore, I think that both scaremongering and underplaying the risks are both bad form, and could result in people making bad decisions both personally and in their business lives. So a bit of questioning of the reports is an important part of the process.

If that means you think I’m on my high horse, then so be it. Taking everything as read is as irresponsible as questioning everything. There is a responsible middle ground, and I think that’s where the vast majority of people on this blog are waling right now.

Sorry, I missed #362. However, I’ve learned one of the reasons why volcanic ash is so detrimental to the engines is that silicic ash melts to glass and thus clogs the engines. But the same must be true for sand clouds, no?

@ Jón363: very interesting. Yes there’s lightning in some of those shots, but that sure as hell looks like large-scale fountaining to me too – which we haven’t seen before in this phase of the eruption as far as I know?

Perhaps it’s melted much of what ice it can in the vicinity of the vents, and there was a temporary slowdown in water supply? Or is more basaltic magma making its way to the surface at times now? Which might imply a depletion of the hypothetical more silicic magma chamber, or a new conduit which bypasses it? All speculation, time will tell.

Redoubt is still stirring.
AVO might be increasing the activity level later.
It’s only 6:15 am here and i don’t believe they monitor all night unless it’s in a more active phase.
Teenagers had fun at prom.
Everyone home safe: Thanks, God.
Best!motsfo

Re: why ash is different than sand – volcanic glass has a much lower melting point than sand, which is made up of small clasts of minerals instead of glass. Melting at 600C rather than 900C can make a big difference.

Re#370 Steve. Desert sand is almost pure silica which probably has a much higher melting point than the ash. Nevertheless desert sand causes all kinds of problems to jet engines. I expect someone could give us a good lecture on the problems it caused to military aircraft in Iraq.

@motsfo, if you check the other webicorder, not much is going on. RSO is closest to the summit and dome. We’ve had an uptick in quake activity recently, so it’s possible that the ‘corders are picking that up as well.

Yesterday I saw a link that showed a suspicious (for lack of a better term) formation near White Island in NZ too. Very busy planet lately.

Just a note on the difference between say sand from a dust storm and volcanic dust.
Surface sands tend to be polished, ie rounded, that also influences the melting points as mentioned – even if they are the same stuff almost. Volcanic ash on the other hand is irregular and crystaline – sharp.
I dont know anything about turbine flow, but in general nice round particles in a fluid (air) would statistically rarely even touch the surfaces due to laminar boundaries. On the other hand irregular shaped particles will in effect smash through fluid flows and cause all sorts of micro turbulence on surfaces – inside the engine.
Or in other words, if I wanted to put a nice polish on a piece of brass, Saharan sand would be good for blasting. If I wanted to take old paint layers off and a few millimetres off the surface, volcanic dust would be perfect.
At least that is my take on it, dredging up some old fluid mech lecture memories – Meaning I might be wrong…
Either way I wouldn’t be keen to test the idea out in jet over Europe at the moment.

On the subject of ash clogging engines. In 1980 my cousin was an Engineer on the Union Pacific Railroad. He was working in the Yard at Davenport, Wa. when the St.Helens cloud hit.
The old SW1500 EMD loco that he was running has what would
pass as an air filter, but limited in it’s capapcity to filter
out Volcanic ash. Also, being a Diesel Electric the dusty ash was shorting the circutry. The Yard boss was an idiot, he kept insisting that the ash was “no different than snow”.
he finally relented when the the loco quit working in the middle of the Yard…

@Boris #350
Are you saying that we shouldn’t be having this discussion because we might get it wrong so should leave it to the experts on the ground who have access to the live information and they should only talk amongst themselves. Isn’t that what happened with the climate scientists which is why they are in the mess they are now?

Yes lots of the people here don’t really have a clue and are learning along the way. We can know what’s happening right now but we can only second-guess what’s about to happen (if anything).

Sorry to be blunt but I do get annoyed when people try and stop good discussion. Yes the media will sensationalise any news like this and put a doom and gloom spin on it but it doesn’t mean we should stop…

At least most of the information here is more factual than most of the news reports in the press.

All of this will only help to raise it in the public eye and help the chance of securing more funding.

One other thing I wanted to mention regarding the deglaciation-volcanism connection:
I don’t think anyone quote in the original article means that you need the pressure release of ice melting to have abundant volcanism. Instead, I think they mean it can amplify the volcanism. Remember, magmatic systems are complex with complex feedback cycles. R. de Haan, you are right to point out that you don’t need the ice cap to melt to produce volcanism and we don’t see new volcanism on the eastern US due to glacial rebound, this doesn’t preclude the idea that when the system is in the right conditions, that ice melt could help produce more volcanism. The fact we see undersea volcanism or the high levels of volcanism in Iceland during the Little Ice Age likely has nothing to do with these pressure arguments – different parts of the complex system were taking part and the loss of ice was not part of it. However, with the evidence I’ve read (and some referenced above), the loss of ice can amplify volcanism – it doesn’t create new volcanism and isn’t needed – but rather it can help things along. We can definitely have abundant volcanism without it, but I wouldn’t dismiss it offhand. Now, whether or not melting will change things on a human timescale is a different story.

I think that we (outside Iceland) owe a lot to many Icelanders for their support here, and their time to post pictures and help to understand the fine points of Icelandic.

Mila and Vodafone also deserve some credit for sharing their bandwith with the world with their webcams. Too bad that Vodafone is out now outside Iceland, but for the time it lasted (I have been following this eruption since the beginning), they deserve our thanks for great images.

And finally, this blog is adds to the experience – kudos to the owner, as well as the regular contributors. Great information and comments, in a very civilized tone.

The only downside to this whole event is the hardships the residents and “flyers” have to face…

When I read Boris’ #350, I must admit I felt I was being admonished for trying to comment without having the knowledge to factually report what I saw, which is true. Apparently, I wasn’t alone in feeling this. On the second reading, I got the impression that we, as a community, were being admonished because we did not appreciate the extremely delicate position of Dr Magnús Tumi Guðmundsson and other official volcanologists who cannot speak freely because doing so could potentially cause more damage than the realisation of a (reasonable) worst-case scenario. This too is true.

Since there is some confusion here, Dr Behncke, could you please clarify? If I, personally, have offended I will not take exception if you point out where and how, and I will do my best to “mend my ways”.

This blog has been the best source of information i have found in one area regarding the EJ eruption. The many opiions and the differing view points have only served to enrich this experience for me and many others also. This has become a true communication center were as most blogs have never reached that point. All who contribute here should be congratulated, I for one am most grateful to be able to witness this as it unfolds with so many others.

All: I think Boris was just trying to reiterate what I have mentioned before – we need to be careful not to think we know more than the scientists in Iceland working day and night to understand this eruption. I know it is exciting – and the media has the tendency to “ambush” scientists (like my 8:45 AM call from the AP). And if you work for the government, you have the extra layer of what can be said and what can’t – see “Supervolcano”, the movie, but without all the dark, windowless rooms.

Doug C: I bet they meant 2500F, which is still ~1350C – and if the magma is andesitic or close, it should be erupting closer to 1000C maybe. Nothing like not fact-checking.

@Boris 350. That’s very intresting: 70 to 80 million cu.m.so far erupted. Does the following estimate have any validity?:
Eyjaf is 700,000years old, and has contributed roughly 10km of additional crustal depth over and above the 10km from mid-ocean ridge activity. That makes a crustal accretion rate of around 1/70 metre per annum, or about 3metres since Eyjaf last erupted 200 years ago. The area covered by Eyjaf is roughly 250sqkm, so total volume magma accreted under Eyjaf since last eruption very approximately 0.75 cubic km or 7.5×10^8 cubic metres. That’s around 10-fold greater volume of magma accreted than has erupted to date.
On that basis Eyjaf could currently be regarded as 10%spent.
But:
What fraction of rising magma erupts typically, and how much solidifies within a volcano of this type?
Is the eruption history of Eyjaf, or crustal accretion from the ‘plume’, likely to have been linear over 700,000 years?
How would this guesstimate of the rate of Eyjaf’s acretion/eruption compare with measuremts made on neighbouring short period volcanoes? Katla, Hekla etc.

@Topher (#387) and Suw (#368) – I am most delighted that this discussion is there, certainly I would not at all want to stop it also because I’m learning from it, too! I just wanted to appeal to some folks out there to leave some of the work to the volcanologists because that’s what their job is, and they often risk their lives in it. There’s furthermore tremendous pressure on them in a crisis like this and they need to weigh their words a million times before speaking them, and before posting them on the internet. The news media often do their bit to contort the information, and we just had the same here at Etna, a couple of days ago, when declarations of our director were cited on the web site of the local Catania newspaper in a hilariously altered way.

The risk of exaggerating or underestimating a risk is tremendous, because the data that are available, with all the modern instruments and elaborate software and knowledge that we have, still leave a lot of space for different interpretations and discussion. Volcanoes provide messages that are often not all that clear. So if volcanologists sometimes struggle to understand them, imagine how much some volcano fan sitting on the computer from the morning to the evening will be able to make out of them. And then there’s the people you deal with, whose lifes and property are at stake. Many of them want to hear they’re safe unless there is a 100 per cent certainty that there is danger, and only then, if at all, they’re willing to move; and then, if the announced disaster does not materialize, it’s serious s**t hitting the fan. Consider all this and then you might understand why the information that is coming through from the volcanologists appears somewhat filtered and apparently excessively reassuring.

That said, the eruption we’re seeing here in these days is certainly a landmark event for our science, it’s of a magnitude that you see once or twice per year globally, and it’s not yet over. I would say it’s somewhere in the league of Okmok and Kasatochi 2008 and Sarychev 2009, and of these it resembles most Okmok. Just look at a photo like this (0f the current eruption):http://www.flickr.com/photos/baldvinh/4529204422/
and then at one of Okmok in the summer of 2008:http://www.avo.alaska.edu/image.php?id=14435

Yes, there are lots of photos showing fountaining of incandescent material, so we see some less interaction of magma with ice and/or water it seems, and some. Do occasionally check Flickr, searching for Eyjafjallajökull or eldgos, and you will come across more and more breathtakingly beautiful photographs of this eruption, many showing the stunning display of lightning at night (by the way, the lightning is typical for a water-rich eruption column, you see much less of this in dry eruption columns).

Hi All. Just a thought, chicken and egg-wise, the melting of the ice-caps could be caused by the increased heat under the ground warming the sea, rather than the melting ice-caps releasing the trapped magma. The hot spot under North America is large enough to warm the polar region. Volcanic release then cools the earth and then the atmosphere. See http://www.medievalacademy.org/pdf/Volcanoes.pdf for historical references.

Peter – ratios of intrusive (doesn’t erupt) to extrusive (erupted) magma are ballpark at best, but for a hotspot like Iceland, something like a 3:1 to 6:1 (intrusive:extrusive) is reasonable. As for rates over time, mostly like the growth of the volcano was not constant through time, but like punctuated and uneven.

For people interested in the intrusive/extrusive relationships, a great place to start is a paper by Crisp from 1984 in the Journal of Volcanology and Geothermal Research called “Rates of magma emplacement and volcanic output” (Vol. 20, p.177-211)

“we need to be careful not to think we know more than the scientists”…

Wise words, I hope they are heeded in all areas…

“With the weather we are encountering now — clear blue skies and obviously no dense ash cloud to be seen, in our opinion there is absolutely no reason to worry about resuming flights,” said Steven Verhagen, vice president of the Dutch Airline Pilots Association and a Boeing 737 pilot for KLM.

Thanks to all of you who are educating us about volcanology. From what some people say, the main cause for the high-reaching volcanic ash is the interaction between hot magma and water (or ice). Would it be feasible to pre-emptively break or drain the glacier (e.g., with explosives), at least at the immediate vicinity of the eurption site? Or rather, would human intervention increase the risk of a more violent eruption?

Although Shelley posted a link that we are quite familiar with here, a quick re-read in light of the most recent eruption phase points to the accuracy of dike intrusion location estimates for the 1994 and 1999 swarm-intrusion event analysis – just south of the crater rim and close to the first fissure eruption location.

The Institute/IMO must be under considerable pressure from European airspace authorities, who are in turn being pushed hard by the airlines and airport management, to provide estimates of what may happen next.

I can empathize and understand Boris’ cautionary regarding press misinterpretation of statements – he’s been in the same boat with Mt Etna’s eruptions.

The press may monitor this web blog, but it cannot stand as an authoritative source.

To us amateurs, it looks as if there is a significant rise in activity “below” while our eyes tell us that it is not resulting in much action “on top”. Ergo, it’s building up for “something big”. That’s the amateur interpretation.

Then we read that professionals think that the eruption is decreasing and may die down any day. This may be the correct interpretation if one has all the data, but makes little sense to us who are not privy to it.

Volcanic tremors still appear to be increasing, from Jon’s helicorder and vedur.is data.

The ash cloud has been reported to not have grown in size today (if I remember correctly its height this morning was just 5-6 Km). So, could this this elevated seismic activity mean that the magma chamber is being recharged while the eruption is continuing at a mild rate? Or rather, and more simply, that since much ice on the volcano summit is gone, high ash plumes are not generated even if the eruptive flow is strong?

The mountain is really hopping this morning on the webcorder. What are the latest guesses on what that means?

As far as ash vs. sand, most good points raised here but also know that the air friction in a jet engine heats the turbines up past their melting point. The only reason they stay intact is that these very expensive fans have thousands of tiny holes that inject cooling air. If those holes get blocked by tiny beads of melted glass then the engine is destroyed. You also have to consider the effect of sand on the leading edges of the turbofans, not to mention the leading edges of the airelons and other things that make the airplane go where you want it to.

Another point raised on the pilot’s network is that planes and engines are certified for almost any possibility. There is actually a standard for how many birds an engine can suck in without destruction — and flight instructions on how to deal with it. Such information does not exist for volcanic ash because as of yet nobody has figured out how to deal with it other than by avoidance. Alas, some of the stuff is invisible to both visual and radar.

I hope that they have the planes that are on standby well covered up. I was in Eugene, OR for the St Helen’s eruption and even though we were mostly upwind of the eruptions that dust would get everywhere. It can destroy car paint in an instant if you are not careful about how you remove it. It is really horrible stuff, not like anything else that I have experienced. Definitely not like walking on the bach in sand.

Motsfo, I understand about teens. I have a 70yro one that I have to run around a bit. LOL Anyway, thanks for the info. I know I am a bit late, but I go to bed before you do. Keep us posted on whatever is going on up there. I can check with the AVO as I have their site in my favorites.

Now I have to catch up. There have been about 200 posts since I was on last night!

Some of you may have come across my previous post (#408) where I explained a bit my previous (#353) statement that a few of you may have taken as a bit rude. But let me explain a bit more. I do work in an agency like the Nordvulk and the IMO, only that it’s in Italy and it’s called INGV (Istituto Nazionale di Geofisica e Vulcanologia). Differently from the Icelanders, the Italian people are a bit more hot-blooded and would never handle a crisis like Eyjafjallajökull as coolly and reasonably as the former.

So I let you imagine what goes on here once something happens, like the 6 April 2009 L’Aquila earthquake. All of a sudden an entire people becomes experts on the subject and everybody feels free to criticize scientists for not having been able to predict the earthquake, and there are all those people who work in a bank or in a hospital or do gardening or repair cars, soccer players, bus drivers, housewives, whatsoever. They feel they can judge whether mistakes have been made by the INGV and whether a person who publicly proclaimed to have found a means of predicting a catastrophic earthquake at least 24 hours in advance was right.

Now imagine a seismologist (or a group of scientists) says there’ll be a huge earthquake in Tokyo within no more than 24 hours … and then imagine a similar scenario in Naples, Italy … and then imagine the earthquake has not yet happened after 24 hours. I don’t think I have to explain any further …

Off topic but I do not understand the purpose of these “test flights” with civilian aircraft with celebrity CEOs aboard. It really looks like a way to pressure the scientists and regulators. I assume that the relevant European agencies will fly properly equipped test aircraft to monitor the airspace when conditions warrant — and that the scientists will take the data and let us know when it is most probably safe to resume flight.

If you are a scientist or regulator keep firm. It isn’t the executives who are going to get blamed when an airplane goes down — “but you guys are supposed to know when it is safe, we just rely upon your judgement!”

Jón and Mr Moho, I agree that’s a good high VEI 3 or low 4 in terms of volume. Obviously the VEI is meant to apply to the instantaneous explosivity and if a volcano emits 500 million cubic meters of tephra during an eruption that lasts 10 years, that would make it at best a VEI of 2. But here we have indeed a significant eruption, and the high levels of tremor are interesting (though the tremor of 13-14 April is no longer visible and therefore lacks for comparison). That could mean that something is on the way up, which would’t be that surprising, after all.

I know this link has been posted in this thread already, but I missed it first time round and just wanted to point it out to anyone who hasn’t followed it yet. I mean, wow. Just wow. Amazing photography:

I have a idea on why the harmonic tremors are increasing, while the activity is reaming low at top.

It is most likely that there is a great volume of magma pushing it way up the volcano now and that is increasing the tremor noise. But that creates a drop in activity at the top of the crater. When the magma that is pushing up the crater gets there, it is going to make a explosion on the larger scale. That is the only logical explanation that I have at the moment. But I do hope that scientists at IMO and HI figure this out before it is too late. Because it is not long before that magma reaches the surface in the top crater.

Re: ‘why ash is different than sand’ – “volcanic glass has a much lower melting point than sand, which is made up of small clasts of minerals instead of glass. Melting at 600C rather than 900C can make a big difference.”

Something I found out while looking up the properties of the component of the ash, Sodium oxide (Na2O)is used in glass making to lower the melting point of the silica mixture.

In the chem analysis report, this ash averages 5.25% Na2O over the five samples.

I just would like to say, that we all can be very grateful that experts like Boris, Erik and others are willing to spend their time for helping us to understand what is going on at planet earth regarding volcanoes and similar phenomena! At least I’m very grateful for this and already have learned a lot from them during the last few years.
Don’t forget, we are not paying anything for this service.

Couldn’t also that amount of melted ice (water) makes the volcano breaks and slide ?
i’ve seen a study about rain on volcano which can result (when enough water in the main structure) in a “structure collapsing”.
Could that happens because of icecap melting and flooding inside the structure ?

speaking about icecap, i’m more worried about Greenland (mount redoub) and Antarctica (isn’t there volcanoes as well ?)

Comments released earlier by experts, and quoted here as a news story, after a recon flyover suggest that the caldera meltwater is draining smoothly and not pooling, with a reported incised flow path along the outlet glacier.

Thanks Jón for the links containing the whole tremor graph since the onset of this latest eruptive episode. Actually, there is a rise in the past few hours but it’s far less conspicuous than the peaks on 13-14 April. So I would say something is on the move but I am not certain it’s very big. It’s also neat how we can see, on 17 April, the intermittent nature of the eruption, with breaks characterized by almost no activity alternating with powerful bursts.

The ash plume seen in the Valahnúk web cam appears relatively weak in this moment, but it seems more continuous than yesterday, from the few times it’s been visible.

If you read Boeing’s instructions it is clear that they left one thing out — PRAY! (Not that I believe in it.) One thing I forgot to mention is that the pitot tubes may clog up — that is what part 9 about flying “unreliable airspeed” procedures means. Airspeed is important to planes, too slow and you crash too fast and you break up. The Air France disaster was most likely caused by the pitot tubes clogging due to ice because all of the fancy avionics depend upon knowing how fast the craft is moving through the air (GPS speed is not a useful substitute…)

So if you hit an ash cloud, you throttle down, make a wide sweeping descending turn, and prepare for a stall. Oh by the way, all of your flight avionics may go out (except for a tiny backup auto horizon) so you have to fly constant speed, except that you just throttled down and are descending. All of the avionics go out so you fly visual, except that the windscreen has turned opaque. Oh right, now the engines just went out and you have to do an emergency restart while putting an oxygen mask over your head.

Still want to fly out of London?

The other problem with Boeing’s instructions is that they assume that you know that you are in an ash cloud; apparently you can suffer rapid severe damage in ash that is not visible.

@Tennyson Lee, The spikes where due to flood water from the glacier. As the water did create a lot of noise on its way down Eyjafjallajökull.

@Boris Behncke, I am fearing that it might be big. The reason why the tremor plot is not bigger then it is might be because the whole thing is still under pressure. But we will see what happens and where this eruption is going.

@henrik Love the Popper quote. Can you give me his(her) full name so I can read? thnx (I’m working thru an online version of swift as I watch the volcanos;-)

@angela Thank you for the beautiful collection of pics and data from the eruption

@boris and erik Thank you for being so kind and generous to the fans of this blog.

Over the years, I’ve realized that non-scientists need certainty, while scientists deal with uncertainty, which leads to very difficult and ugly situations. I’ve also realized that the only opinions that count are those of one’s peers. The opinions of all others are driven by their personal fears and demons. It’s difficult not to take those opinions personally, but it’s easier to think of them as a table: that is, if a table is in the way, you go around it. If you walk into the table, you say ouch and move on, forgetting the ouch.;-D

Regarding Boris’ post #429, I certainly do understand the awful position that a lot of scientists find themselves in when it comes to predicting events such as earthquakes, eruptions, etc. It is a very difficult position to be in, and I sympathise with anyone who has to make official statements about uncertain events, particularly to a less level-headed population.

Science communication around complex and unpredictable events is really difficult, not just because it is simply not always possible to make clear and definite judgements/predictions, but also because journalists often have their own agenda. I say this not just as someone who has a degree in geology, but also as someone who sometimes works as a science/tech journalist and who has spent a lot of time observing the media.

We are, though, entering a difficult phase for any scientist communicating about this eruption. Official reports are going to come under a lot more press scrutiny than would be the case if the ash cloud weren’t affecting international flights. Sadly, most of the journalists covering this story won’t have much grounding in geology (I think we’ve all seen evidence of that!) and so clarity is going to be paramount.

@Suw: I, though not an expert or specialist of any kind, can give out one definite fact: Tomorrow there’ll be several newspaper editors looking totally titfaced because they changed ‘may’ to ‘will’ because it made for better copy, and then the volcano went and did its own thing in complete disregard of their headlines.

Why can’t the geologists simply tell the media the truth – that they can’t predict what’s going to happen. I know there’s pressure to say something when a microphone is shoved in your face or you’ve got a reporter/journalist on the other end of the line, but that’s why most spokespersons take courses in media relations and know that they’re always looking for that “quotable quote” that sells rather than informs.

@Frito Lay. Scientist DO say over and over (broken record technique) “we can’t predict, we can only give probabilities”. The media (and the pols in government) then strip the statement of uncertainty and run off for ratings and votes.

re. engines and ash, aside from safety of flight, engine maintenance costs are a crucial economic consideration for the airlines. The engines represent more than 25% of the value of the entire aircraft and are the biggest single source of maintenance expense. So if a aicraft flies through the ash and experiences even a slight level of damage and performance degradation, not only has that flight turned from profit to loss, but the aircraft will be grounded while the engines are repaired or replaced. Since the whole system runs on the assumption that engines degrade at a predictably low rate, a surge of fleet wide ash damage will rapidly deplete all the available spares and repair capacity. In some sense, the airlines are relying on the authorities to keep them all on the ground at the same time, so the hurt is shared. Once KLM or another airline gets permission to start flying again, they will all want to get back in the air so they don’t spill traffic to competitor airlines. If the eruption continues I expect that they will figure out a number of airspace control work-arounds that will allow routes to open and close on a more selective basis as conditions change and more data is made available

Parclair! (#454) Sir Karl Popper 1902-1994. This entry in the “Stanford Encyclopaedia of Phiosophy” gives a good summary – http://plato.stanford.edu/entries/popper/ As is evident from the summary, his was a remarkable intellect and as a middle-aged undergradute I was enthralled by the incisiveness of his logic (see part 3. “The Problem of Demarcation”).

PS. My Popper quote is not verbatim, but rather my memory of it and may contain errors.

I think the geologists are understandably cautious about what they say because the media often will distort it. Qualifiers often will be removed. As was aptly depicted in a recent Dilbert cartoon, one becomes very cautious in saying anything after having been bitten by a distorted version in the past. The safest though perhaps not always wisest course is to say nothing which is least likely to be misquoted.

I think the biggest difficulty in explaining any eruption is no one really knows with certainty what is going to happen next. There is simply not enough data to say.
I have heard the phrase “complex system” many times. The systems are not only complex but hidden under kilometers of rock,ice and water.
A tip of my hat to all the scientists reading the “morris code” of the earth and understanding what is is saying.

While we are waiting to see if anything happens maybe this is a good place to ask:

What sort of techniques can be used to detect very fine ash particles at a distance? From the looks of this eruption,
the “boffin” who figures out how to retrofit aircraft avionics to detect fine ash is going to earn a spot right up there with Wright brothers.

4.
Dr. O
Michigan
Someone wrote this in the NYT comments section. What do you think?
“April 18th, 2010
1:04 pm
The big joke is that if the airlines still had some of those ‘dinosaur’ airliners, such as DC6-7-8, etc. they could be flying right now because piston engines have air filters on the intakes and the piston engines don’t have to fly at the extreme altitudes the jets do for fuel economy, and the extreme altitudes is where the fine ash is floating… Sure, the passengers would take twice as long to get there (250 knots versus 500 knots) but they would be getting there!”

On the media: Usually they will distort just about anything you say and it isn’t always the media. I had a incident years ago where I was threatend by the son of a lady that was running a group home. She was in the hospital at the time and he was a convicted felon for drugs and should not have been there in the first place. Then next day I reported the situation and they had me saying things I did not say. So it can happen regardless of whether it is the media or people taking reports for social services.

I really do feel for the people that have to give reports because people want to know. Well, sometimes they don’t know. I’m for giving them some slack and taking some responsibility for what I decide to do in a given situation.

@Boris, I still remember watching an old film from the 1930s of an Etna eruption and it is creeping along the street and the police are trying to get a lady to leave here home and she is refusing. The lava front looked to be about 30′ high and was only about a short block away!

Sometimes we people just don’t want to leave our stuff! Just remember the people that live around Mayon. If they leave, others will steal what they have and it is ALL they have. So lets give the volcanologists and geologist a big hand of applause for the work they do. As Boris said, they often risk their lives geting the info for us. Just yesterday, I saw a picture of a volcanologist on Kilauea taking a sample from a skylight. Not far from where the person was standing, you could see cracks in the upper area of the skylight and it looked like it could colapse at any moment. The person was taking a sample and it was risky business.

I am hoping that no one gets harmed in any way while working to get info on Eyjaf. It is more dangerous now than it was which goes without saying.

Just spouting off a bit. Not at anyone who posts here, just on my soap box. I hope I have not offended anyone.

The MSNBC story uses a lot more qualifiers:
(www) msnbc.msn.com/id/36624082/ns/travel-news/

“Up to 50 percent of commercial flights in Europe could be back in the air on Monday…’The forecast is that there will be half of flights possibly operating tomorrow. It will be difficult; that’s why we have to coordinate,’ Diego Lopez Garrido, whose country holds the European Union presidency, told reporters”

Same press conference, very different report. It’s all in the emphasis. I agree re: the irresponsibility of using absolutes in situations like this.

The technology has been hammered out for in-flight ultra fine particle abd aerosol capture and analysis by various spectrometric methods, by NASA and many university/research center groups. Light-scattering would be the simplest method, but has lower mass detection limit issues.

But maybe we can give the aviation folk a hand.

The ash discharge physics, surface charge capacity, and wet-silica mass are ideal for accumulating and transferring charge from large to small particles in the immediate plume mixing zone, downfield of the eruption.

We saw that in the photos, in a link posted earlier today. Lots of lightning.

I would be looking for an intermittent light polarization signature. Ice particles might be an issue (they also will polarize-field align), so background non-ash signature would need to be established.

That should give an indicator of ash particle presence, but not necessarily particle density. That would have to be determined by inflight particle filter capture and analysis.

Got astronomers? Better than milk! They’re the clever scientists who first detected this phenomenon and reported on it several years ago, wrt to Saharan dust that also carried a surface charge and also circuit-field aligned.

A “de-ashing” system would be a very tough sell even if it were technically feasible (which I doubt, but am an EE, not an ME). Imagine the liability if nothing else. And this eruption (or even series of eruptions) would be long past by the time such as system could be developed, tested, and approved by the regulatory authorities. It also seems doubtful commercial airlines would want to pay for the costs (both in in acquisition and maintenance) for something to protect against a once-in-a-lifetime (hopefully) occurrence.

Forgot to mention: particles tend to to sort by mass in a plume with the smallest particles being carried the furthest by the wind. However, the surface charge density on the smaller particles will also cause them to rise (an interesting physics story in itself), making them especially difficult to detect, especially as they won’t be scattering light as non-aligned particles might.

I wonder if it’s possible to use a laser or very short wavelength radar to detect ash prior to a plane actually flying onto it. If the ash is electrically conductive or light reflective, it seems like it may be possible.

13/10/1918
A major event started yesterday, when Katla, who has been quiet since 1861 began to erupt. Inhabitants at Vík felt little earthquakes leading up to the eruption and they lasted for a short while. A short while later great plumes were seen hovering over Mount Hetta and that confirmed that Katla had boiled over. Travelers, who were at Múlakvísl river, had to leave as the river fled forward, mixed with icebergs in such ferocity and speed, flowing over everything in its path, that no living man has never witnessed anything like that is his life.

At Vík:
We managed to reach the phone operator at Vík at 18:30 last night. The People there are of course afraid. However people who live on the sands, between already flooded areas, are far worse off. It is feared that travellers were on the sands when it became flooded but any news of their fate could be far off as it is hard to reach people east of Múlakvísl river.
A great amount of lightening activity was seen above Vík near the glacier but no ash had yet fallen to the ground last evening. Judging by the shape of the plume there has been little wind at Katla so far.

Shortly after the eruption started the plume became visible in Reykjavik and it reached high up into the sky. It got larger and larger as time passed and when it got dark, firestrokes and lightening were vislble in the plume. You could say, that the whole eastern sky was a raging fire. As far as we know, no eruption has been seen in such a way from Reykjavik, so we could speculate that this is the biggest eruption for a very long time.

Just a non-scientific observation, I am not a seismologist or a vulcanologist so take it for what it is worth…..Every time the volcano has calmed down for any length of time….it surprised us all…both scientists and laymen. Every time the newspapers have posted a story about the imminent demise of this volcano…..BOOM! By the same token when the newspapers were reaching a critical mass over the volcano….what happens? Does anyone else see a pattern here?

Just another observation but it would seem that God/Gaia/Odin/The Blind Watchmaker or whoever else is in charge has a real sense of humor. So far this volcano has accomplished something that is pretty amazing….It has shut down air travel…and pointed out just how tenuous the sinews are that underpin our 21 Century world….Like Klaatu it did this without taking any lives so far…All I can say is Thank God/Jesus/Mohammad/Buddha/Krishna/Odin/Ahura Mazda/Jah and anyone else I may have left out for this blessing!…Just an observation but we should all just be darn grateful it isn’t any worse and hope for the best;) That’s it for me until 4pm….I am going to go walk the dogs and enjoy a beautiful day….the volcano will tend to its self;) “Klaatu barada nikto”

It would be great if it was possible to identify the exact location of the harmonic tremor, meiby with triangulation. If we new the depth and location of the source it would help in guessing the reason for the harmonic tremor.

Is this impossible to do with harmonic tremor, and is it because harmonic tremor is a continous signal?

“what does it mean when the low frequency tremor plot is increasing more than the mid and high freq plots”

I would think it would not be a “good” sign. What happens to the pitch of a tea kettle if you increase the size of the hole in the lid? The pitch drops. My gut instinct would be that increasing lower frequency tremor might mean the movement of a larger quantity of material at depth.

other wise if you have a breathing problem already it can aggravate it by lacerating the inside of of the lungs, it is basically like crushing glass super fine then breathing it with the added extra of the toxic chemicals that coat it sulpher and fluoride compounds most common

I don’t think anyone is questioning climate change. The climate changes on a regular basis, they are called seasons. The question is man’s role in climate change, specifically global warming. The “evidence” as you call it is tainted and biased towards profiteers and globalists who want to make us aerobic earthlings pay for this insanity willingly without any objection or questions at all. Did you simply ignore the leaked emails concerning this or are they are not “evidence” as well? If Al Gore feels a little too warm it is because his head is stuck up somewhere it should’nt be. If you want to join him then by all means do so. Don’t force this idiotic idea on people and expect them to but into it. The “scientists” who are involved in this scam need to be prosecuted and any licenses they may have need to be revoked. This crap is along the same line as the health care scam being forced on us. The issue is access to “Health Care,” not access to health insurance. One should not cloud these issues with ignorance.

Did you simply ignore the leaked emails concerning this or are they are not “evidence” as well?

The investigation into the stolen e-mails demonstrated that there was no ‘there’ there. The only people still pushing that story are of a piece with the 9/11 truthers, Obama birthers, and CIA killed Kennedy nutcases.

Already “proven” by Non-government influenced scientists that glaciers are not melting. What you are seeing are several years of very cold weather to cause snow falling on the glaciers to freeze and build up over time. since we are seeing a “normal” climate now, the ice “frozen snow” is melting. The result may well cause the volcanic conditions you describe but not global warming. After all, since the earth has cooled about half a degree in the past twenty years, I don’t think we will catch fire in the next few hours. Get a grip and do the science instead of just believing every word you hear because some famous person says it’s so. THINK!!!!!!